The transition to and from fullscreen mode is asynchronous. During the transition, IsFullscreen() will return the previous value and no 2D or 3D device can be bound. The transition ends at DidChangeView() when IsFullscreen() returns the new value. You might receive other DidChangeView() calls while in transition.

The transition to fullscreen mode can only occur while the browser is processing a user gesture, even if PP_TRUE is returned.